PROJECT SUMMARY Pneumonia is the leading infectious cause of death among young children worldwide, with most cases occurring in low and middle-income countries. Children who survive pneumonia have an increased risk of impaired lung development, reduced lung function, and chronic respiratory disease in adulthood. Our preliminary data from an ongoing cohort study in Uganda demonstrate a high rate of chronic respiratory symptoms among children who had a prior episode of pneumonia and near-universal exposure to household air pollution from biomass fuel combustion. Reducing household air pollution may provide an opportunity to improve lung development in children with pneumonia and prevent development of chronic respiratory disease. My central hypothesis is that infants recovering from pneumonia are at particularly increased risk of reduced lung function growth when exposed to household air pollution, and that reducing exposure to household air pollution will improve lung function growth. In this K23 Mentored Patient-Oriented Career Development Award, I will test this hypothesis within my mentors? already established study of 8,700 children in Uganda through an observational study and pilot intervention trial with the following Specific Aims: (1) to measure the effect of pneumonia on the rate of lung function growth among young infants, (2) to measure the effect of particulate matter exposure (PM2.5) on lung function growth, and (3) to determine the feasibility and acceptability of a clean cookstove intervention in families of young infants with pneumonia. The accompanying training plan will allow me to build on an existing foundation of clinical and epidemiologic skills to (1) develop expertise in infant lung physiology and testing, (2) develop expertise in household air pollution research methods, and (3) develop skills in qualitative research and clinical trial design for low-resource settings. This study will provide critical preliminary data and a training platform to launch my career as an independent investigator in global respiratory research, with a long-term goal of understanding the mechanisms of impaired lung development and developing interventions to improve respiratory health for children and adults living in low-income countries. Supported by mentors and collaborators who are internationally-known experts in pneumonia, household air pollution, infant lung function, qualitative research, and clinical trial design, the proposed research will leverage the wealth of resources available at Massachusetts General Hospital/Harvard Medical School and a longstanding collaboration with Mbarara University of Science and Technology in Uganda. This proposal addresses NHLBI?s Strategic Vision Objective #4, to investigate factors that account for differences in health among populations, and is directly responsive to a research gap identified in the 2014 NHLBI Workshop on the Primary Prevention of Chronic Lung Diseases, to study how early childhood exposures affect development of lung function and subsequent risk of COPD and other chronic respiratory diseases.